1. Field of the Invention
The present invention relates to, in general, a sealing device for laminated heat exchangers and, more particularly, to a sealing device provided with a gasket capable of preventing heat exchanging mediums from being leaked from the junction between neighbored heat exchanging plates, thereby improving the heat efficiency of a heat exchanger.
2. Description of the Prior Art
As well known to those skilled in the art, a laminated heat exchanger consists of a plurality of heat exchanging plates. The assembling method of such a laminated heat exchanger will be described below. First, a gasket is set on the heat exchanging plate. Thereafter, supporting bars are inserted into holes formed on the heat exchanging plates. Such a plurality of heat exchanging plates, with the supporting bars, are clamped together and so a complete heat exchanger is obtained.
In a conventional method for attaching the gasket to the heat exchanging plate, adhesives are preferentially applied to a longitudinal groove, formed on the edge of the heat exchanging plate, prior to seating the gasket into the groove.
However, such a conventional method is problematic in that the application of the adhesives requires a lot of time and labor. Also, it is difficult to maintain the cleanliness of the adhesive surface of the heat exchanging plate. In addition, the firstly applied adhesives are more quickly hardened than that of the lastly applied adhesives because the adhesives are wholly applied along the lengthy longitudinal grove. Thus, the part of the gasket, located at a position of the primarily hardened adhesives, may be easily separated from the heat exchanging plate. Furthermore, when an existing gasket has to be exchanged with a new one, the adhesives, existing on the heat exchanging plate, have to be removed.
In order to overcome the above problems, a sealing device for such heat exchangers, without using any adhesives, is proposed.
For example, a sealing device for such heat exchangers is disclosed in U.S. Pat. No. 3,244,227 (Apr. 5, 1966). In the above U.S. Patent, the sealing device comprises a heat exchanging plate, having an extended part at its edge, and a gasket, including a fitting tap. Also, a groove is formed around the edge of the heat exchanging plate and so the fitting tap is fitted into the groove. In addition, a plurality of holes are formed on the extended part, while a plurality of pins are formed at the lower portion of the fitting tap. Thus, the pins are effectively inserted into the holes.
However, the above sealing device according to the U.S. Pat. No. 3,244,227 has the following problems. That is, the hole of the heat exchanging plate has the same diameter as the pin of the gasket because the pins of the fitting tap have to be tightly inserted into the holes of the plates. Thus, it is difficult to insert the pins into the holes, thereby reducing work efficiency while assembling the gasket with the heat exchanging plate. On the other hand, when the diameter of the holes is large than that of the pins, the gasket may be easily separated from the heat exchanging plate.
In addition, a sealing device for such heat exchangers is disclosed in U.S. Pat. No. 4,905,758 (Mar. 6, 1990). In the above U.S. Patent, the sealing device comprises a heat exchanging plate, having a groove at its edge, and a gasket, including a fitting tap. Also, step parts are formed at the outer portion of the groove, while a plurality of holes are formed at the side portions of the step parts. Thus, the fitting tap is effectively inserted into the holes.
However, the above sealing device according to the U.S. Pat. No. 4,905,758 has the following problem. That is, the gasket may slip toward the holes because the holes are formed at the side portion of the groove, thereby reducing a sealing effect.
In order to overcome the above problems, a sealing device for heat exchangers is disclosed in Korean Patent Publication No. 91-3072. The sealing device according to the above Korean Patent is schematically shown in FIGS. 5 and 6.
As shown in FIGS. 5 and 6, the sealing device comprises a heat exchanging plate 5 and a gasket 1. The heat exchanging plate 5 includes both a wave-shaped portion at its edge 6 and a longitudinal groove 7 at a position inside the wave-shaped portion. The wave-shaped portion of the plate 5 has a plurality of alternately arranged ridges 9 and furrows 8.
The gasket 1, to be set on the heat exchanging plate 5, has a configuration, which is integrally formed with a connecting part 2, supporting part 2A and two free end parts 3 and 4. One end of the connecting part 2 is perpendicularly formed on the body of the gasket 1, the other end of the connecting part 2 is also perpendicularly connected to the central portion of the supporting part 2A. That is, the supporting part 2A is parallel with the body of the gasket 1.
In addition, the two free end parts 3 and 4 are formed at both ends of the supporting part 2A in such a manner that the two free end parts 3 and 4 vertically extend toward the body of the gasket 1, respectively.
Thus, the gasket 1 is set on the heat exchanging plate 5 in such a manner that the connecting part 2 of the gasket 1 comes into contact with the upper surface of a furrow 8, and the two free end parts 3 and 4 closely come into contact with the lower surfaces of two ridges 9, respectively.
However, the above sealing device for heat exchangers is problematic in that the construction of the gasket 1 is complicated due to the connecting, mounting parts 12 and 12A, and the two free end parts 3 and 4. Also, it is difficult to fit the two free end parts 3 and 4 of the gasket 1 into the lower surfaces of the ridges 9. In addition, when the heat exchanging plate 5 is installed in the heat exchanger, the conventional sealing device requires a space for the supporting part 2A because the supporting part 2A is protruded toward the outside of the heat exchanging plate 5.